Jerry Cuttler, a tireless researcher on the topic of the health effects of low level radiation, sent me an article titled Toward Improved Ionizing Radiation Safety Standards from the July 2011 issue of Health Physics, a peer-reviewed journal about radiation safety. (Unfortunately, like many peer reviewed journals, Health Physics is not available for free online. It is possible to purchase individual articles or to gain access if you have a membership or access to a university or corporate library.)
The article explains in clear, but scientific terms, how radiation at low average levels can result in increasing the latency period of cancer development past the end of a natural lifespan. We all have the potential for developing cancer, but we also have finite lives. Dr. Raabe’s research has led him to the conclusion that low average doses of radiation that might add up to a substantial cumulative dose do not kill off cancer cells, but they delay the ability of those cells to do any real damage until after their host organism is dead from other causes anyway.
Dr. Raabe reaches an an important conclusion that should cause policy makers to require regulators to read his paper and pay attention to his recommendations. That is especially true for those policy makers that are deeply concerned about budget expenditures and claim to be looking under every rock for ways to cut spending.
Clearly the development of a radiation-induced malignant tumor from either protracted ionizing radiation exposures or acute exposures is not the result of a single random interaction of the ionizing radiation with an isolated cell. Hence, the term stochastic as used by the ICRP (International Commission on Radiological Protection) is not appropriate. The following conclusions indicate that major revisions of the ICRP methodology and standards are needed, and other currently accepted ionizing radiation risk models should be improved to provide more meaningful and realistic estimates of ionizing radiation cancer risk:
- Cancer induction risk associated with protracted or fractionated ionizing radiation exposure is a non-linear function of lifetime average dose rate to the affected tissues and exhibits a virtual threshold at low lifetime average dose rates;
- Cumulative radiation dose is neither an accurate nor an appropriate measure of cancer induction risk for protracted or fractionated ionizing radiation exposure except for describing the virtual threshold for various exposures; and
- Cancer promotion risk for ongoing lifetime biological processes is a relative process as seen in the RERF (Radiation Effects Research Foundation) studies of the Japanese atomic bomb survivors for brief high dose-rate exposures to ionizing radiation. It cannot be used to estimate cancer induction risk from protracted or fractionated ionizing exposures over long times and at low dose rates.
The current ICRP radiation protection recommendations certainly provide a high level of safety and protection for radiation workers and the public. Radiation safety has been the most important goal of the ICRP, and their recommendations have met that goal with distinction. However, the ICRP risk estimates and response models for protracted or fractionated ionizing radiation exposures and long-lived internal emitters seriously overestimate the risks of low doses. Reasonably accurate cancer induction risk estimates are needed to avoid expensive over-regulation and to bolster the scientific foundation of radiation safety regulations and analysis. Many of the current environmental radiation safety standards are inappropriately low and prohibitively expensive to enforce.
The current ICRP models of radiation carcinogenesis can be misleading. Revision of the radiation safety standards is needed that clearly distinguishes between radiation cancer promotion as observed in the atomic bomb survivor studies and radiation cancer induction as observed for long-lived internal emitters. In particular, the ICRP needs to revisit and revise the standards currently recommended for ionizing radiation-induced cancer. Recommended standards should be considered that are based on lifetime average dose rate to sensitive tissues in the case of internally-deposited, relatively long-lived radionuclides and other protracted or fractionated exposures rather than on cumulative or committed dose.
(Emphasis in original.)
John Stossel provides a another way to understand some of the effects that Dr. Raabe and others (his paper includes a full two column page of references) have noticed in their years of intensive study of the real health effects of measured or computed radiation exposures on a variety of population groups.
The web presence of Paul Voosen (March 15, 2011) – Radiation and the Linear Hypothesis
GAO Testimony (July 8, 2000) RADIATION STANDARDS: Scientific Basis Inconclusive, and EPA and NRC Disagreement Continues